Your EV battery life is 40% more than company’s claim: Stanford Study

Research by Stanford University and SLAC National Accelerator Laboratory has shown that the existing batteries in EVs are expected to last up to 40% more in real-world driving conditions than the expected predictions in laboratory tests.

Differing from lab tests, real-world conditions contain long highway trips, heavy traffic, extended parking and short city trips. Lab tests consider a constant rate of discharge and rapid cycling which usually do not lead to an accurate prediction of batteries’ lifespan for everyday use, the study published in Nature Energy highlighted. 

Therefore, the research has established that EV batteries can last longer in real-world conditions. Meanwhile, as a battery makes up around one-third of an EV’s price, future and current EV owners can feel a bit more ease from the new study. 

However, traditional lab tests don't accurately predict how long EV batteries will last, according to Simona Onori, a senior author and associate professor at Stanford. She also noted that real driving conditions, such as frequent braking, acceleration, and rest periods, actually help batteries last longer than previously thought.

After testing 92 commercial lithium-ion batteries over a two-year period with varying discharge profiles, researchers found that realistic driving behaviours, such as frequent stops and accelerations, resulted in longer battery life. A machine learning system assisted in determining the elements that contributed to this surprising endurance, such as sudden, abrupt accelerations that slowed down the deterioration of batteries. This disproves the earlier theory that batteries suffer damage from acceleration peaks.

The study investigated two forms of battery ageing: time-induced ageing (caused by batteries sitting unused) and cycle ageing (caused by several charge-discharge cycles). For average EV users with intermittent automobile use, time-induced ageing holds more significance than cycle ageing. The study discovered a balance between these two forms of ageing, indicating that automakers should upgrade battery management software to increase battery longevity under practical circumstances.